JP6378979B2 - Expansion device - Google Patents

Description

  The present invention relates to an expansion device including a balloon that can be expanded at a target site such as a stenosis in a body lumen.

  A balloon catheter as an expansion device is used to expand a stenosis portion generated in a living body lumen such as a coronary artery blood vessel. The balloon catheter generally includes a long catheter having a lumen through which a fluid flows, and a balloon that is provided on the distal end side of the catheter and is expandable by the fluid. Then, a balloon catheter is inserted into the in-vivo lumen, and the balloon supplied with the fluid is inflated, so that the narrowed portion in the in-vivo lumen is expanded.

  For example, when a stenosis occurring in a blood vessel is expanded with a balloon catheter, a particularly large expansion force is required by the balloon, particularly in a stenosis that has become hard, such as a calcified lesion. For this purpose, a low compliant balloon (high pressure resistant balloon) is used, but a phenomenon may occur in which the balloon slips off the lesion while the balloon is pressurized to the target expansion diameter. This is because when the balloon is pressurized, the balloon is slowly expanded using the inflator, so that the balloon is displaced from the lesion and the force escapes before reaching the target expansion diameter.

  In addition, for cases where it is difficult to expand the stenosis, there is an example where the balloon is intentionally burst (ruptured) and the expansion of the stenosis is instantaneously attempted. However, in this case, the radial dimension of the balloon at the time of rupture cannot be controlled and is uncertain, and there is a risk of blood vessel damage because the contrast agent in the balloon is ejected into the blood vessel.

  On the other hand, Patent Documents 1 and 2 include two balloons, a radially inner balloon and a radially outer balloon, and a balloon catheter in which the radially inner balloon is ruptured to inflate the radially outer balloon. Is disclosed (see claim 3 of patent document 1 and claim 1 of patent document 2).

JP-A-2-224668 Japanese Patent No. 3767655

  The technique described in Patent Document 1 aims to realize balloon expansion in accordance with the inner diameter of a lesioned part without drawing out a catheter once guided to the lesioned part. That is, in the technique described in Patent Document 1, when the expansion diameter of the inner balloon is not sufficient, the outer balloon having an expansion diameter larger than that of the inner balloon is increased by further increasing the pressure and rupturing the inner balloon. The stenosis is enlarged by expanding.

  In addition, the technique described in Patent Document 2 has a stent attached to the outside of the balloon catheter, and the problem is that the end portion of the stent spreads in a flared manner while entering the lumen of the stent. . That is, the technique described in Patent Document 2 first inflates the outer balloon by applying pressure to the inner balloon to expand the balloon to expand the central portion of the stent, and further increasing the pressure to rupture the inner balloon. The remaining portion of the stent is expanded.

  However, none of the techniques described in Patent Documents 1 and 2 specifically considers the behavior of the inner balloon when it bursts. Therefore, when the inner balloon is ruptured, the pressure applied to the inner surface of the outer balloon becomes irregular, and the balloon cannot be uniformly expanded. For this reason, the expansion force of the balloon that instantaneously expands the stenosis is not sufficiently exhibited.

  This invention is made | formed in view of an above described situation, and makes it a subject to provide the expansion device which can expand a balloon more uniformly and instantly.

In order to solve the above problems, an expansion device according to the present invention includes a long main body having a lumen through which a fluid circulates, and a balloon that is provided on a distal end side of the main body and is expandable by the fluid. The balloon is provided on the outer periphery on the distal end side of the main body, and is provided so as to cover a first balloon portion communicating with the lumen and a radially outer side of the first balloon portion, and a closed space is radially inward. A second balloon part formed on the peripheral surface of the first balloon part, and the first balloon part has a radial dimension smaller than that of the second balloon part when expanded. A plurality of regions having a smaller burst strength than the other regions are provided at a plurality of locations, and the region having a lower burst strength is partially thinned by extending a part of the peripheral surface radially outward. it is characterized in that it is a region where there .

In such a configuration, the operator inserts the expansion device into the in-vivo lumen from the distal end side, and positions the balloon at a target site such as a stenosis. Then, by introducing the fluid through the lumen, the inner first balloon portion is first expanded. The inner first balloon part is set to have a smaller radial dimension (expansion diameter) during expansion than the outer second balloon part, so even if the inner first balloon part is expanded, it will not rupture. The expansion diameter (target expansion diameter) intended by the surgeon is not reached. Therefore, the balloon does not slip from the target site when the inner first balloon portion is expanded. When the pressure of the fluid is further increased, the inner first balloon portion is ruptured in a region having a low rupture strength provided at a plurality of locations. At this time, due to the pressure increased in the inner first balloon part, the fluid is ejected at a plurality of locations toward the inner surface of the outer second balloon part, and the outer second balloon part is instantly expanded to expand the purpose. Reach the diameter. Moreover, since the expansion energy reaches the inner wall of the target site such as the stenosis part through the outer second balloon part due to the release of the high pressure generated when the inner first balloon part ruptures, the stenosis part etc. is instantly expanded. The expansion force can be exhibited sufficiently.
That is, according to such a configuration, an expansion device capable of expanding the balloon more uniformly and instantaneously can be provided.
Therefore, since the balloon expands uniformly and instantaneously at the time of expansion, the stenosis portion or the like can be reliably expanded to the target inner diameter without detaching from the target site such as the stenosis portion.

  In the present invention, the lumen branches into a first path connected to a pressurizer capable of pressurizing the fluid and a second path different from the first path on the proximal end side of the lumen. A pressure adjusting unit that adjusts the pressure of the fluid is connected to the second path, and the pressure adjusting unit is slidably disposed within the cylinder, and one surface of the pressure adjusting unit is A piston that is exposed to the pressurizing space that communicates with the lumen; and a pressing member that applies a pressing force to the pressurizing space on the other surface of the piston, and the pressing member before the expansion of the first balloon portion. The pressure applied to the piston is set by the pressing member so as to be lower than the pressure at the time of rupture of the first balloon part.

In such a configuration, before the expansion of the inner first balloon portion, the piston is in a position on the pressure space side by being pressed by the pressing member. When the pressure of the fluid is increased, the pressure of the fluid exceeds the pressure applied to the piston from the pressing member, and the piston is moved backward by the pressure of the fluid to reach the position on the pressing member side. The position on the pressing member side is a position where the pressure applied to both surfaces of the piston is balanced. When the pressure of the fluid is further increased and the inner first balloon portion is ruptured, the pressure tends to drop due to the sudden expansion of the volume, and as a result, the piston is moved forward to the pressure space side by the pressing member. . Thereby, the pressure from a pressure adjustment part is transmitted to an outer 2nd balloon part instantaneously.
That is, according to such a configuration, the pressure drop due to the rapid expansion of the volume when the inner first balloon part is ruptured can be supplemented by the supply of pressure from the pressure adjusting part. Therefore, when the inner first balloon part is ruptured, the outer second balloon part can be instantaneously expanded by reacting more quickly.

  In the present invention, the pressure applied from the pressing member to the piston when the first balloon portion is ruptured is higher than the pressure when the second balloon portion reaches a predetermined radial dimension at the time of expansion. Thus, it is set by the pressing member.

  According to such a configuration, since the pressure supplied from the pressure adjusting unit is sufficiently high when the inner first balloon part is ruptured, the second balloon part is more quickly and reliably made to have a predetermined radial dimension. Can be expanded.

  ADVANTAGE OF THE INVENTION According to this invention, the expansion device which can expand a balloon more uniformly and instantly can be provided.

It is the schematic which shows the structure of the balloon catheter which concerns on one Embodiment of the expansion device of this invention. It is an expanded sectional view of the balloon periphery shown by FIG. It is a schematic perspective view of the 1st balloon part shown by FIG. It is a schematic perspective view of the 1st balloon part which concerns on a modification. It is a schematic perspective view of the 1st balloon part concerning other modifications. (A) is a schematic enlarged sectional view showing a state before expansion of the first balloon part of the pressure adjusting unit shown in FIG. 1, and (b) is a state immediately before the first balloon part of the pressure adjusting unit shown in FIG. 1 is ruptured. It is a general | schematic expanded sectional view which shows a state. (A) is sectional drawing which shows typically the state of the balloon immediately before the burst of the 1st balloon part, (b) is sectional drawing which shows typically the state of the balloon immediately after the bursting of the 1st balloon part.

Embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
Note that, in the drawings shown below, the same members or corresponding members are denoted by the same reference numerals, and redundant description is omitted as appropriate. In addition, the size and shape of the member may be schematically represented by being modified or exaggerated for convenience of explanation.

FIG. 1 is a schematic view showing a configuration of a balloon catheter 100 according to an embodiment of the expansion device of the present invention.
As shown in FIG. 1, a balloon catheter 100 according to this embodiment is an expansion device including a balloon 20 that can be expanded at a target site such as a stenosis in a living body lumen. Here, a case will be described in which the balloon catheter 100 is used to expand a stenosis portion generated in a coronary artery blood vessel serving as a living body lumen to improve blood flow.

  The balloon catheter 100 includes a catheter 10 as a long main body having an expansion lumen 15 (see FIG. 2) through which fluid flows, a balloon 20 provided on the distal end side of the catheter 10 and expandable by a fluid, And a hub 30 attached to the base end side. In the present invention, the “tip” of the balloon catheter 100 refers to the end on the side inserted into the living body lumen, and the “proximal end” refers to the end opposite to the “tip”.

FIG. 2 is an enlarged cross-sectional view around the balloon 20 shown in FIG.
As shown in FIG. 2, the catheter 10 includes a double tube having a tube shape, and includes an inner tube 11 and an outer tube 12 through which the inner tube 11 is inserted.

  The inner tube 11 is a cylindrical body and is formed from a flexible synthetic resin material such as polyolefin or polyamide elastomer. The inner tube 11 has an inner diameter that is large enough to allow the guide wire W (see FIG. 1) to pass therethrough, and the inner space of the inner tube 11 constitutes the guide wire lumen 13.

  The inner tube 11 preferably has ring-shaped markers 14 and 14 formed of an X-ray opaque material such as a metal such as platinum on the outer periphery of a region located in the balloon 20. By having the markers 14 and 14, a clear contrast image of the markers 14 and 14 can be obtained under fluoroscopy. Therefore, the position of the balloon 20 provided on the distal end side of the catheter 10 inserted into the in-vivo lumen. Can be easily recognized (confirmed).

  The outer tube 12 is a cylindrical body, and is formed of a flexible synthetic resin material such as polyolefin or polyamide elastomer. The inner diameter of the outer tube 12 is larger than the outer diameter of the inner tube 11, and the space formed between the inner peripheral surface of the outer tube 12 and the outer peripheral surface of the inner tube 11 holds a fluid for inflating the balloon 20. An extension lumen (lumen) 15 to be distributed is configured. Further, the distal end surface of the outer tube 12 is located on the proximal end side with respect to the distal end surface of the inner tube 11. That is, the inner tube 11 protrudes from the distal end opening of the outer tube 12 toward the distal end side.

  The balloon 20 is provided on the outer periphery on the distal end side of the catheter 10, and includes a first balloon portion 21 communicating with the expansion lumen 15 and a radially closed outer space 23 provided to cover the radially outer side of the first balloon portion 21. And a second balloon portion 22 formed on the radially inner side.

  Specifically, the proximal end side of the first balloon portion 21 is joined to the distal end side of the outer tube 12 in a liquid-tight manner, and the distal end side of the first balloon portion 21 is joined fluid-tightly to the distal end side of the inner tube 11. Further, the proximal end side of the second balloon portion 22 is liquid-tightly joined to the distal end side of the outer tube 12 and at a position proximal to the joining portion with the first balloon portion 21, and the inner tube 11 The distal end side of the second balloon portion 22 is liquid-tightly joined to the distal end side and at a position closer to the distal end side than the joining portion with the first balloon portion 21. However, part or all of the axial end of the second balloon part 22 may be in close contact with the outer peripheral surface of the axial end of the first balloon part 21. As a bonding method of the balloon 20, a conventionally known bonding method such as heat fusion is used.

  The first balloon portion 21 and the second balloon portion 22 can be expanded and contracted (folded) by a change in internal pressure. Therefore, when a fluid is introduced into the inside, a cylindrical shape (cylinder) surrounding the catheter 10 is provided. It is configured to expand to the shape. FIG. 2 shows a state where the first balloon portion 21 and the second balloon portion 22 are expanded for easy understanding. The radial dimension (expanded diameter) D1 when the first balloon part 21 is expanded is set smaller than the radial dimension (expanded diameter) D2 when the second balloon part 22 is expanded.

  In this embodiment, the inner first balloon portion 21 is ruptured and the outer second balloon portion 22 is inflated. Therefore, the outer second balloon portion 22 is designed to have higher pressure resistance than the inner first balloon portion 21.

  The balloon 20 is required to have flexibility to enable expansion and contraction, and pressure resistance to ensure a certain degree of expansion force for expanding a hardened stenosis such as a calcified lesion. It becomes. For this reason, as a constituent material of the balloon 20, it is preferable to use a material having low compliant or non-compliant properties such as polyethylene terephthalate (PET), nylon 6, nylon 66, nylon 12, and the like. However, the constituent material of the balloon 20 is not limited to the above.

FIG. 3 is a schematic perspective view of the first balloon portion 21 shown in FIG.
As shown in FIGS. 2 and 3, the peripheral surface 24 of the first balloon portion 21 is provided with a plurality of regions 25 having a smaller burst strength than other regions of the peripheral surface 24. The region 25 is desirably provided uniformly in the circumferential direction. Here, “the region 25 is uniformly provided in the circumferential direction” means that the region 25 is not arranged at a specific circumferential position on the circumferential surface 24, and the existence ratio of the region 25 is circumferential. It is almost uniform. In the present embodiment, a plurality of regions 25 with low burst strength are formed in a uniform shape on the peripheral surface 24 of the first balloon portion 21 in a circular shape.

  As a manufacturing method of the first balloon part 21 and the second balloon part 22, for example, a method (blow molding method) in which a film is formed on the inner surface of a blow molding die by blow molding a cylindrical parison is used. Is done. In this case, for example, a large number of substantially hemispherical recesses are formed on the inner surface of the mold, and the parison is extended radially outward in the recesses at the time of blow molding, thereby reducing the thickness, thereby reducing the burst strength region. 25 can be formed. However, the region 25 having a low burst strength is not limited to the case where it is formed by partially reducing the thickness as described above. For example, the mechanical strength such as tensile strength is partially low. You may form by comprising with material.

FIG. 4 is a schematic perspective view of the first balloon portion 21a according to the modification. FIG. 5 is a schematic perspective view of a first balloon portion 21b according to another modification.
The region having a smaller burst strength than the other regions of the peripheral surface 24 is not limited to the shape shown in FIG. For example, as shown in FIG. 4, a plurality of regions 25a having a low burst strength are formed on the circumferential surface 24 of the first balloon portion 21a in a straight line parallel to the axial direction at equal intervals in the circumferential direction. May be. Moreover, as shown in FIG. 5, the area | region 25b with small burst strength may be formed in the peripheral surface 24 of the 1st balloon part 21b so that a spiral shape may be exhibited. In the present invention, the region 25b is formed such that a plurality of regions having low burst strength are continuously connected and circulated, and one of the examples in which the regions having low burst strength are provided at a plurality of locations. To do.

  Returning to the description of FIG. 1, the hub 30 includes a hub body 31 and an expansion port 32 branched from the hub body 31. The expansion port 32 communicates with the first balloon portion 21 (see FIG. 2) of the balloon 20 via the expansion lumen 15 (see FIG. 2). The expansion lumen 15 is used for introducing and discharging a fluid for expanding the balloon 20. For example, a liquid such as a contrast medium can be used as the fluid.

  In this embodiment, the balloon catheter 100 is an over-the-wire type (OTW type) having a structure in which a guide wire W that is inserted in advance into a lumen in a living body is inserted from the distal end to the proximal end of the balloon catheter 100. However, the balloon catheter 100 may be a rapid exchange type (RX type) having a structure in which the guide wire W is exposed from an intermediate position of the catheter 10.

  The expansion port 32 has an expansion port main body 33 and a pressure adjustment port 34 branched from the expansion port main body 33. A pressurizer 35 capable of pressurizing a fluid such as an indeflator is connected to the expansion port main body 33 via the first path 41. On the other hand, a pressure adjustment unit 50 that adjusts the pressure of the fluid is connected to the pressure adjustment port 34 via the second path 42. That is, the expansion lumen 15 (see FIG. 2) branches into a first path 41 and a second path 42 different from the first path 41 on the proximal end side of the expansion lumen 15.

  6A is a schematic enlarged cross-sectional view showing a state before expansion of the first balloon portion 21 (see FIG. 2) of the pressure adjusting portion 50 shown in FIG. 1, and FIG. 6B is shown in FIG. 3 is a schematic enlarged cross-sectional view showing a state immediately before the first balloon part 21 of the pressure adjusting part 50 is ruptured. FIG.

  As shown in FIG. 6, the pressure adjusting unit 50 includes a cylinder 51 that has a substantially cylindrical shape, and a pressure that is slidably disposed in the cylinder 51 and that one surface communicates with the expansion lumen 15 (see FIG. 2). A piston 52 exposed in the space 54 and a pressing member 53 that applies a pressing force to the pressure space 54 side on the other surface of the piston 52 are provided. In this embodiment, a spring member such as a compression coil spring is used as the pressing member 53. Further, a seal member 55 such as an O-ring is mounted in an annular groove formed on the outer peripheral surface of the piston 52.

  The pressure Ps applied to the piston 52 from the pressing member 53 is based on the pressure P1 (for example, 25 atm (about 2532.5 kPa)) when the first balloon portion 21 is ruptured before the first balloon portion 21 (see FIG. 2) is expanded. Is set by determining the characteristics of the pressing member 53 so that the pressure Psa is lower (for example, 20 atm (about 2026 kPa)). The pressure Ps applied from the pressing member 53 to the piston 52 is a pressure P2 (for example, about 20 atm (about 20 atm) when the second balloon portion 22 reaches the expanded diameter D2 (see FIG. 2) when the first balloon portion 21 is ruptured. 2026 kPa)), the pressure Psb (for example, 25 atm (about 2532.5 kPa)) is set by determining the characteristics of the pressing member 53. Here, the pressure Ps applied from the pressing member 53 to the piston 52 is a value obtained by dividing the pressing force (biasing force) by the pressing member 53 by the cross-sectional area of the piston 52.

Next, referring to FIG. 7 in addition to FIG. 1 to FIG. 6, with respect to the method of using the balloon catheter 100 configured as described above, taking as an example the case of expanding a stenosis occurring in a coronary artery It demonstrates with the effect | action.
7A is a cross-sectional view schematically showing the state of the balloon 20 immediately before the first balloon portion 21 is ruptured, and FIG. 7B is a schematic view showing the state of the balloon 20 immediately after the first balloon portion 21 is ruptured. FIG. In addition, in FIG. 7, the inner tube | pipe 11 shows a side surface instead of a cross section.

First, the surgeon selects a balloon catheter 100 that matches a target blood vessel diameter from among a plurality of sizes prepared with reference to the expanded diameter D2 of the outer second balloon portion 22.
Subsequently, the operator positions the guide wire W (see FIG. 1) in the stenosis of the coronary artery blood vessel that is the target site under X-ray irradiation. Then, the surgeon inserts the balloon catheter 100 into the coronary artery blood vessel from the distal side along the positioned guide wire W.
Next, the surgeon positions the balloon 20 at the stenosis of the coronary artery blood vessel as the target site while confirming the position of the balloon 20 with the markers 14 and 14 under X-ray irradiation.

  Then, by introducing a fluid through the expansion lumen 15 using the pressurizer 35 (see FIG. 1), the inner first balloon portion 21 is first expanded (see FIG. 7A). Since the expansion diameter D1 of the inner first balloon portion 21 is set to be smaller than the expansion diameter D2 (see FIG. 7B) of the outer second balloon portion 22, the inner first balloon portion 21 is expanded. Even if it does, it will not reach the target expanded diameter (target expanded diameter) until it ruptures. Here, the target expansion diameter is equal to the expansion diameter D2 of the outer second balloon portion 22. Therefore, the balloon 20 does not slip from the target site when the inner first balloon portion 21 is expanded.

  When the pressure of the fluid is further increased using the pressurizer 35, the inner first balloon portion 21 is ruptured in each of the regions 25 (see FIGS. 2 and 3) having a small rupture strength provided at a plurality of locations. (Refer FIG.7 (b)). At this time, due to the pressure increased in the inner first balloon portion 21, the fluid is ejected at a plurality of locations toward the inner surface of the outer second balloon portion 22, and the outer second balloon portion 22 is instantaneously used. The expansion diameter D2 is reached. In addition, due to the release of the high pressure generated when the inner first balloon 21 is ruptured, the expansion energy reaches the inner wall of the target stenosis via the outer second balloon 22 so that the stenosis is instantly expanded. The expansion force to be exerted can be fully exhibited.

  As a result, the inner diameter of the inner wall of the stenosis of the coronary artery blood vessel is instantaneously expanded to ensure the target blood vessel diameter. Thereafter, the balloon catheter 100 and the guide wire W are extracted from the coronary artery blood vessel, and the procedure is completed.

Thus, according to the balloon catheter 100 of this embodiment, the balloon 20 can be expanded more uniformly and instantaneously.
Therefore, since the balloon 20 is uniformly and instantaneously expanded at the time of expansion, the stenosis portion or the like can be reliably expanded to a target inner diameter without detaching from the target portion such as the stenosis portion.

  In the present embodiment, the expansion lumen 15 is connected to a pressure adjusting unit 50 that adjusts the fluid pressure, and the pressure adjusting unit 50 includes a cylinder 51, a piston 52, and a pressing member 53. The pressure Ps applied from the pressing member 53 to the piston 52 is a pressure Psa (for example, 20 atm) lower than the pressure P1 (for example, 25 atm) when the first balloon part 21 is ruptured before the first balloon part 21 is expanded. It is set with the pressing member 53 so that it may become.

In such a configuration, before the inner first balloon portion 21 is expanded, the piston 52 is brought into contact with the stopper by being pressed by the pressing member 53 and located at the pressure space 54 side (FIG. 6A). )reference). When the pressure P of the fluid is increased, the pressure P of the fluid exceeds the pressure Ps (= Psa) applied to the piston 52 from the pressing member 53, and the piston 52 is moved backward by the pressure P of the fluid, so that the pressing member It comes to a position on the 53 side (see FIG. 6B). The position on the pressing member 53 side is a position where the pressure applied to both surfaces of the piston 52 is balanced. Further, the fluid pressure P is further increased, and when the inner first balloon portion 21 is ruptured, the pressure Ps applied to the piston 52 is also equal to the fluid pressure P = P1 (for example, 25 atm) when the first balloon portion 21 is ruptured. The pressure has increased to Psb. When the inner first balloon portion 21 is ruptured, the pressure P tends to drop due to the rapid expansion of the volume, and accordingly, the piston 52 is moved forward to the pressurizing space 54 side by the pressing member 53. As a result, the pressure Ps from the pressure adjusting unit 50 is instantaneously transmitted to the outer second balloon unit 22.
That is, according to such a configuration, the pressure drop due to the rapid expansion of the volume when the inner first balloon part 21 is ruptured can be supplemented by the supply of the pressure Ps from the pressure adjusting part 50. Therefore, when the inner first balloon portion 21 is ruptured, the outer second balloon portion 22 can be expanded instantly by reacting more quickly.

  In the present embodiment, the pressure Ps applied from the pressing member 53 to the piston 52 is the pressure P2 (for example, about 20 atm (about 20 atm) when the second balloon portion 22 reaches the expanded diameter D2 when the first balloon portion 21 is ruptured. The pressure member 53 sets the pressure Psb (for example, 25 atm (about 2532.5 kPa)) higher than 2026 kPa)).

  According to such a configuration, since the pressure Ps supplied from the pressure adjusting unit 50 when the inner first balloon unit 21 is ruptured is sufficiently high, the second balloon unit 22 is expanded in a predetermined radial dimension. The diameter D2 can be expanded more quickly and reliably.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to the structure described in the said embodiment, The combination thru | or selecting suitably the structure described in the said embodiment is included. The configuration can be changed as appropriate without departing from the spirit of the invention. In addition, a part of the configuration of the embodiment can be added, deleted, and replaced.

  For example, in the above-described embodiment, the case where the balloon catheter 100 is used for dilating a stenosis occurring in a coronary artery blood vessel has been described. However, a stenosis occurring in a living body lumen other than the coronary artery blood vessel is described. Of course, it can also be used for expansion.

  Moreover, in above-mentioned embodiment, although the catheter 10 as an elongate main body is comprised from the double tube | pipe which has a tube shape, this invention is not limited to this. For example, instead of the inner tube (inner tube 11), a solid shaft may be used, in which case no guide wire is used. Further, the long main body may be constituted by a single shaft, and an expansion lumen for flowing fluid along the axial direction may be formed inside the shaft.

  In the above-described embodiment, the spring member is used as the pressing member 53 of the pressure adjusting unit 50, but the present invention is not limited to this. For example, instead of the spring member, the filler, which is a fluid (for example, air) having a higher compressibility (shrinkage rate) than the fluid flowing through the expansion lumen 15, is the other surface (back surface) side of the piston 52 in the cylinder 51. The space may be filled.

  In the above-described embodiment, the pressure adjusting unit 50 has a mechanical configuration including the cylinder 51, the piston 52, and the pressing member 53, but is not limited thereto. For example, when the pressure in the first balloon portion 21 (pressure in the expansion lumen 15) is detected by a pressure sensor or the like and a pressure drop due to a sudden expansion of the volume when the first balloon portion 21 is ruptured, You may employ | adopt the structure which can perform the electrical control which generates a pressure electrically, such as moving a piston with a motor, and complements a pressure drop part. Furthermore, the pressurizer 35 is configured so as to be able to electrically control the pressurization of the fluid, and the pressurizer 35 performs control to complement the pressure drop when the first balloon portion 21 is ruptured. In this case, the pressure adjusting unit 50 is omitted.

10 Catheter (main body)
15 Extended lumen (lumen)
20 balloons 21, 21 a, 21 b first balloon part 22 second balloon part 23 space 24 peripheral surface 25, 25 a, 25 b area with low burst strength 35 pressurizer 41 first path 42 second path 50 pressure adjusting part 51 cylinder 52 piston 53 Pressing member 54 Pressurizing space 100 Balloon catheter D1 Expansion diameter of the first balloon part (diameter dimension during expansion)
D2 Expanded diameter of second balloon part (dimension in radial direction when expanded)

Claims (3)

A long body having a lumen through which fluid flows;
A balloon provided on the distal end side of the main body and expandable by the fluid,
The balloon is provided on the outer periphery on the distal end side of the main body, and is provided so as to cover a first balloon portion communicating with the lumen and a radially outer side of the first balloon portion, and a closed space is radially inward. A second balloon part formed on
The first balloon part has a smaller radial dimension when expanded than the second balloon part,
The peripheral surface of the first balloon part is provided with a plurality of regions having a smaller burst strength than other regions of the peripheral surface ,
The expansion device according to claim 1, wherein the region having a low burst strength is a region in which a part of the peripheral surface extends radially outward and is partially thinned . The lumen is branched into a first path connected to a pressurizer capable of pressurizing the fluid and a second path different from the first path on the base end side of the lumen;
A pressure adjusting unit that adjusts the pressure of the fluid is connected to the second path,
The pressure adjusting unit includes a cylinder, a piston slidably disposed in the cylinder, one surface of which is exposed to a pressure space communicating with the lumen, and the other surface of the piston toward the pressure space. A pressing member for applying a pressing force,
The pressure applied to the piston from the pressing member before the expansion of the first balloon portion is set by the pressing member so as to be lower than the pressure at the time of the bursting of the first balloon portion. The expansion device according to claim 1.   The pressure member is configured such that the pressure applied to the piston from the pressing member when the first balloon portion is ruptured is higher than the pressure when the second balloon portion reaches a predetermined radial dimension during expansion. The expansion device according to claim 2, wherein the expansion device is set by:

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